How does dsRNA lead to posttranscriptonal gene silencing?

Verified step by step guidance

1. Double-stranded RNA (dsRNA) is recognized by the cell as a signal to initiate the RNA interference (RNAi) pathway.
2. The enzyme Dicer processes the dsRNA into small interfering RNAs (siRNAs), which are typically 21-23 nucleotides in length.
3. These siRNAs are incorporated into the RNA-induced silencing complex (RISC), where they are unwound into single strands.
4. The RISC, guided by the siRNA, binds to complementary mRNA molecules in the cytoplasm.
5. Once bound, the RISC cleaves the target mRNA, leading to its degradation and preventing translation, thus silencing the gene post-transcriptionally.

Key Concepts

Double-stranded RNA (dsRNA)

Double-stranded RNA (dsRNA) is a type of RNA that consists of two complementary strands. It plays a crucial role in the regulation of gene expression and is often associated with viral infections. In the context of gene silencing, dsRNA can trigger cellular mechanisms that target and degrade specific mRNA molecules, thereby preventing their translation into proteins.

RNA interference (RNAi)

RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression by causing the degradation of specific mRNA. This process is initiated when dsRNA is recognized by the enzyme Dicer, which cleaves it into small interfering RNAs (siRNAs). These siRNAs then guide the RNA-induced silencing complex (RISC) to complementary mRNA targets, leading to their silencing.

Post-transcriptional gene silencing

Post-transcriptional gene silencing refers to the regulation of gene expression at the mRNA level, preventing translation into proteins. This process can occur through mechanisms such as mRNA degradation or translational repression, often mediated by small RNA molecules like siRNAs. dsRNA is a key trigger for this silencing, as it activates the RNAi pathway, leading to the targeted destruction of specific mRNAs.